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Mine production index(MPI)-extension of OEE for bottleneck detection in mining

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International Journal of Mining Science and technology 2016年第5期26卷 753-760页

作者： Amol Arun Lanke Seyed Hadi Hoseinie Behzad Ghodrati division of Operation and Maintenance Engineering Lule? University of Technology

Although mining production depends on various equipments, significant amount of production loss can be attributed a specific equipment or fleet. Bottleneck is defined not only by production loss but also by our satisfaction from the equipment. The user satisfaction could be measured as machine *** literatures on performance improvement and optimization of equipment operations assert importance of availability, utilization and production performance as key parameters. These three parameters are useful for evaluating effectiveness of equipment. Mine production index(MPI), which can represent the effect of these factors, has been applied for continuous operation in mining. MPI uses Fuzzy Delphi Analytical Hierarchy Process to determine importance of each three parameter for individual equipment. A case study in a Swedish open pit mine was done to evaluate the field application of *** results reveal that crusher is the bottleneck equipment in studied mine. As a methodical approach,an algorithm which uses MPI and detects bottleneck in continuous mining operation has been proposed.

关键词： Mine production index Bottleneck seeking FDAHP Production analysis

Excessive portal flow causes graft failure in extremely small-for-size liver transplantation in pigs

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World Journal of Gastroenterology 2005年第44期11卷 6954-6959页

作者： Hong-Sheng Wang Nobuhiro Ohkohchi Yoshitaka Enomoto Masahiro Usuda Shigehito Miyagi Takeshi Asakura Hiroo Masuoka Takashi Aiso Keisuke Fukushima Tomohiro Narita Hideyuki Yamaya Atsushi Nakamura Satoshi Sekiguchi Naoki Kawagishi Akira Sato Susumu Satomi division of Advanced Surgical Science and technology Department of Surgery

AIM： To evaluate the effects of a portocaval shunt on the decrease of excessive portal flow for the prevention of sinusoidal microcirculatory injury in extremely smallfor-size liver transplantation in pigs. METHODS： The right lateral lobe of pigs, i.e. the 25% of the liver, was transplanted orthotopically. The pigs were divided into two groups： graft without portocaval shunt （n = 11） and graft with portocaval shunt （n = 11）. Survival rate, portal flow, hepatic arterial flow, and histological findings were investigated. RESULTS： In the group without portocaval shunt, all pigs except one died of liver dysfunction within 24 h afcer transplantation. In the group with portocaval shunt, eight pigs survived for more than 4 d. The portal flow volumes before and after transplantation in the group without portocaval shunt were 118.2±26.9 mL/min/100 g liver tissue and 270.5±72.9 ml./min/100 g liver tissue, respectively. On the other hand, in the group with portocaval shunt, those volumes were 124.2±27.8 ml./ min/100 g liver tissue and 42.7±32.3 mL/min/100 g liver tissue, respectively （P〈0.01）. As for histological findings in the group without portocaval shunt, destruction of the sinusoidal lining and bleeding in the peri-portal areas were observed afl：er reperfusion, but these findings were not recognized in the group with portocaval shunt. CONCLUSION： These results suggest that excessive portal flow is attributed to post transplant liver dysfunction after extreme small-for-size liver transplantation caused by sinusoidal microcirculatory injury.

关键词： Hyperperfusion syndrome Liver regeneration Portocaval shunt Postoperative liver dysfunction Sinusoidal microcirculatory injury Small-for-size liver transplantation

Solvent-free aerobic oxidation of ethylbenzene over supported Ni catalysts using molecular oxygen at atmospheric pressure

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Journal of Natural Gas Chemistry 2008年第3期17卷 293-297页

作者： G.Raju P.Shiva Reddy J.Ashok B.Mahipal Reddy A.Venugopal Catalysis & Physical Chemistry division Indian Institute of Chemical Technology

We investigated the aerobic oxidation of ethylbenzene in the absence of solvent or any additive carried out over Ni on different types of supports namely SiO2, hydroxyapatite, SBA-15, and USY Zeolites. The oxidation of ethylbenzene activities was measured in a round bottom flask immersed in oil bath at known reaction temperature. The physicochemical characteristics of the catalysts were examined by BET surface area, XRD, FT-IR and the oxidation activities were correlated with the acidities of the catalysts obtained by TPD of NH3. It was observed that both hydroxyapatite and USY （13% Na2O） supported Ni catalysts displayed higher ethylbenzene conversion and 80% selectivity towards acetophenone.

关键词： nickel SBA-15 zeolites hydroxyapatite ethylbenzene oxidation TPD of NH3

Accretion onto the Magnetically Charged Regular Black Hole

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Chinese Physics Letters 2017年第7期34卷 38-40页

作者： M.Azam A.Aslam division of Science and technology University of Education Lahore 54590 Pakistan

We investigate the accretion process for static spherically symmetric geometry, i.e., magnetically charged regular black hole with isotropic fluid. W＇e obtain generalized expressions for the velocity （u（r））, speed of sound （cs2）, energy density （ρ（r）） and accretion rate （M） at the critical point near the regular black hole during the accretion process. We also plot these physical parameters against fixed values of charge, mass and different values of equation of state parameter to study the process of accretion. We find that radial velocity and energy density of the fluid remain positive and negative as well as rate of change of mass is increased and decreased for dust, stiff, quintessence fluid and phantom-like fluid, respectively.

关键词： Accretion onto the Magnetically Charged Regular Black Hole

Microwave gel combustion synthesis and sinterability of Nd:GGG nanopowders

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Journal of Rare Earths 2014年第6期32卷 521-525页

作者： Kiranmala Laishram Rekha Mann Neelam Malhan Laser Materials division Laser Science and Technology Centre DRDO

Neodymium doped gadolinium gallium oxide （Nd：GGG） nanopowders synthesized by microwave gel combustion using alanine as a fuel was reported. Metal nitrates solution with alanine fuel was combusted in microwave to give precursor. The micro-wave precursor powder was calcined at different temperatures from 800 to 1100 ℃. Phase pure Nd：GGG formation took place at 800 to 1100 ℃ as observed by X-ray diffraction （XRD） and Fourier transform infra-red （FTIR） spectroscopy. However particle size in-creased with calcinations temperature from 25 nm at 800 ℃ to 200 nm at 1100 ℃.Nd：GGG nanopowder obtained at different calci-nation temperatures were compacted and sintered at 1550 ℃ for 3 h in air. Most densified ceramic was obtained from Nd：GGG nanopowder calcined at 1100 ℃. Microstructure as observed from scanning electron microscopy （SEM） showed that the most densi-fied ceramic, obtained from nanopowder calcined at a higher calcination temperature, had a more uniform grain-size distribution, fewer pores and greater densification. XRD of sintered sample showed retention of phase purity.

关键词： Nd:GGG microwave gel combustion calcinations densification rare earths

A short review on natural gas hydrate, kinetic hydrate inhibitors and inhibitor synergists

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Chinese Journal of Chemical Engineering 2019年第9期27卷 2049-2061页

作者： Wei Ke Daoyi Chen division of Ocean Science and technology Graduate School at Shenzhen Tsinghua University

Gas hydrate-caused pipeline plugging is an industrial nuisance for petroleum flow assurance that calls for technological *** thermodynamic inhibitors such as glycols and inorganic salts suffer from high dosing,environmental unfriendliness,corrosiveness,and economical *** development and use of kinetic hydrate inhibitors(KHIs),mostly polymeric compounds,with their inhibiting effects on hydrate nucleation and growth are considered an effective and economically viable chemical treatment for hydrate ***,the actual performance of a KHI candidate is dependent on various factors including its chemical structure,molecular weight,spatial configuration,effective concentration,pressure and temperature,evaluation methods,use of other additives,*** review provides a short but systematic overview of the fundamentals of natural gas hydrates,the prevailing categories of polymeric kinetic hydrate inhibitors with proposed inhibition mechanisms,and the various synergists studied for boosting the KHI *** research endeavors are in need to unveil the KHI working modes under different *** conjunctive use of KHIs and synergists may facilitate the commercial application of effective KHIs to tackle the hydrate plugging problem in the oil and gas flow assurance practices.

关键词： Hydrate Nucleation Kinetics Hydrate inhibitors Inhibition mechanism Inhibitor synergist

Regulating silver nanowire size enables efficient photoelectric conversion

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Science China Chemistry 2020年第8期63卷 1046-1052页

作者： Jie Xu Kai Wang Yi Li Tao-Tao Zhuang Huai-Ling Gao Yang-Yi Liu Chuan-Xin He Shu-Hong Yu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China Department division of Nanomaterials&Chemistry Hefei National Laboratory for Physical Sciences at the MicroscaleCAS Center for Excellence in NanoscienceDepartment of ChemistryInstitute of Biomimetic Materials&ChemistryUniversity of Science and Technology of ChinaHefei 230026China

The increasing demand for the state-of-the-art transparent conductive electrodes has received great interest in synthesizing silver nanowires(AgNWs)with a uniform diameter that exhibit excellent conductance,transparency,flexibility and mechanical ***,we report the controllable synthesis of ultrathin AgNWs with high aspect ratio via a polyol-assisted *** diameter of AgNWs can be continuously modulated from 20 to 80 nm by simply adjusting the aging *** selfassembled films fabricated by using AgNWs with a diameter of 20 nm as building blocks enable an excellent performance and show a sheet resistance of^30Ω/sq and an optical transmittance of 94%.In addition,such nanowire-based conductive films can keep the excellent flexibility and resistance after bending 10,000 ***,the intelligent dimming films prepared by this AgNW films also have excellent flexibility and stability.

关键词： silver nanowires polyol-assisted process assembly transparent conductive film conductive electrode

Effects of gadolinium addition on the microstructure and mechanical properties of Mg–9Al alloy

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 901-908页

作者： Lavish Kumar Singh Alok Bhadauria Amirthalingam Srinivasan Uma Thanu Subramonia Pillai Bellambettu Chandrasekhara Pai Department of Metallurgical and Materials Engineering Indian Institute of Technology Kharagpur Materials Science and technology division National Institute for Interdisciplinary Science and Technology

This research aims to study the significance of Gd addition(0wt%–2wt%) on the microstructure and mechanical properties of Mg–9Al alloy. The effect of Gd addition on the microstructure was investigated via X-ray diffraction(XRD), optical microscopy, scanning electron microscopy(SEM), and transmission electron microscopy(TEM). The Mg–9Al alloy contained two phases, α-Mg and β-Mg_(17)Al_(12). Alloying with Gd led to the emergence of a new rectangular-shaped phase, Al_2Gd. The grain size also decreased marginally upon Gd addition. The ultimate tensile strength and microhardness of Mg–9Al alloy increased by 23% and 19%, respectively, upon 1.5wt% Gd addition. We observed that, although Mg–9Al–2.0Gd alloy exhibited the smallest grain size(181 μm) and the highest dislocation density(5.1 × 10^(10) m^(-2)) among the investigated compositions, the Mg–9Al–1.5Gd alloy displayed the best mechanical properties. This anomalous behavior was observed because the Al_2Gd phase was uniformly distributed and present in abundance in Mg–9Al–1.5Gd alloy, whereas it was coarsened and asymmetrically conglomerated in Mg–9Al–2.0Gd.

关键词： magnesium rare earth alloying gadolinium microstructure mechanical properties

Impact of weather conditions and building design on contaminant infiltration from crawl spaces in Swedish schools-Numerical modeling using Monte Carlo method

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Building Simulation 2022年第5期15卷 845-858页

作者： Fredrik Domhagen Paula Wahlgren Carl-Eric Hagentoft Department for Architecture and Civil Engineering Division of Building TechnologyChalmers University of TechnologySE-41296GothenburgSweden

Some Swedish school buildings built in the 1960s and 1970s experience indoor air quality problems,where the contaminants are suspected to come from the crawl space underneath the *** poor indoor air quality causes discomfort among pupils and *** an exhaust fan to maintain a negative pressure difference in the crawl space relative to indoors or increasing the ventilation in the classroom are two examples of common measures taken to improve the indoor air ***,these measures are not always effective,and sometimes the school building has to be *** relation between pressure distribution,contaminant concentration in the classroom,outdoor temperature,wind,mechanical ventilation,and air leakage distribution is complex.A better understanding of these relations is crucial for making decisions on the most efficient measure to improve the indoor air *** this paper,a model for contaminant infiltration from the crawl space is used together with the Monte Carlo method to study these *** are performed for several cases where different building shapes,building orientations,shielding conditions,and geographical locations are *** show,for example,that for a building with an imbalanced ventilation system,air is leaking from the crawl space to the classroom for the majority of cases and that concentration levels in the classroom are usually the highest during mild and calm days.

关键词： airtightness air permeability Monte Carlo method infiltration model crawl space indoor air quality